RATE OF REACTION

Question

ZnCO₃+H₂SO₄ --> ZnSO₄+H₂O+CO₂

The average rate of reaction is 0.638 cm³ s^-1.If 0.067 g of zinc carbonate is used,what is the time taken to complete the reaction?

(Molar volume of gas at room temp =24 mol dm^-3)

(Relative atomic mass: H=1,C=12,O=16,Zn=65,S=32)

Answer 1

molar mass ZnCO₃ = 65 + 12 + 48 = 125 g/mole

moles of ZnCO₃ present = 0.067 g x 1 mole/125 g = 5.36x10^-4 moles

moles of CO₂ produced = 5.36x10^-4 moles ZnCO₃ x 1 mole CO₂/mole ZnCO₃ = 5.36x10^-4 moles CO₂

Liters of CO₂ produced = 5.36x10^-4 moles x 24 L/mole = 1.29x10^-2 liters = 0.012 L (note: molar volume is not 24 mol dm-3, but rather is 24 L/mole).

0.012 L = 12 ml = 12 cm³

To find the time required to generate this volume, we use the rate of reaction.

0.638 cm³/sec (x sec) = 12cm³

x = 18.8 seconds